The
purpose of this feature is to give scout leaders, educators and naturalists an
idea of some of the natural events coming up each month. We will try to
cover a variety of natural events ranging from sky events to calling periods of
amphibians, bird and mammal watching tips, prominent wildflowers and
anything else that comes to mind. We will also note prominent
constellations appearing over the eastern horizon at mid-evening each month for
our area for those who would like to learn the constellations. If you have
suggestions for other types of natural information you would like to see added
to this calendar, let us know!
Though we link book references to nationwide sources, we encourage you to
support your local book store whenever possible.
Notes From September 2021
On September 6th we had a break from the rain and a brief but beautiful
preview of fall. A cold front swept through, and the high
pressure region that followed kept the sky cloud free for several days. The
nights were cool enough that a flannel shirt felt good as I walked down to
the observatory. Though the tree crickets were calling everywhere, the
calls of the katydids slowed to an occasional "did-did" .
I could hear Southern Leopard Frogs calling from the pond near the
observatory. Their peak breeding season is in the early spring, but they
will often begin calling again in the fall as the nighttime temperatures
mirror the spring temps. You can sometimes find their egg masses in ponds
in the fall.
I heard a sharply rising wail from the tree line to the west of the
observatory. I thought it might be the beginning of a coyote chorus, but
it turned out to be yet another vocal feat of a Barred Owl. Although I
hear both the, "Who-cooks-for-you, Who-cooks-for-you-all" and the
descending, "Whooooo-awwww" calls quite a bit, the rising call is one that
I don't hear very often. It's sharp and smooth and very unlike the raspy
begging calls of young Barred Owls. Another Barred Owl joined the first
and they were soon cackling back and forth. The Milky Way stretched from
the south-southwest horizon overhead and then down into Cassiopeia.
I made some adjustments to the camera's autoguider and then
decided to image the Helix Nebula, a very large planetary nebula in
Aquarius.
By the time I left the observatory to let the telescope finish its
session, the Pleiades were well up into the eastern sky. Aldebaran, the
red eye of Taurus the Bull, looked balefully at me as it cleared
the treetops.
The Helix Nebula, September 6th - 9th, 12.5" Newtonian Telescope
and ZWO ASI2600 MM camera. Total exposure time between 10 and
11 hours through red, green, blue and hydrogen alpha filters.
The name planetary nebula is a misnomer. These nebulae were given the
name because some of them looked similar to the distant gas giant planets
Uranus and Neptune. The Helix Nebula, 650 light-years distant, is one of
the closest.
The reds you see in the above image are mostly due to ionized
hydrogen, while the blue areas represent ionized oxygen. The nebula is
about 2-1/2 light-years in diameter. If you zoom into the image you can
see small "cometary knots"
around the inside diameter, many showing a tail
extending radially away from the central star. Each one of these knots is
about the size of our solar system! You'll be able to pick out more detail
in the larger version of the image here.
There are also some very distant galaxies in the image. Probably the
easiest of them to spot is below and slightly to the left of the bright
golden star on the right side of the nebula. It's a distant edge-on galaxy
that is shining through the nebulosity of the nebula. Its distance
is probably in the neighborhood of several hundred million light-years.
The American Astronomer L.H. Aller called planetary nebulae, "The wreaths
nature places around dying stars". When a star between one and eight solar
masses reaches the end of its lifetime it swells to become a red giant and
then casts off its outer layers. The core of the star
contracts and becomes a white dwarf. The white dwarf radiates enough
energy to cause the expanding shell of gas to fluoresce, and the shell
becomes visible to us.
Finder Chart for the Helix Nebula (From Sky Safari)
Though the Helix Nebula is faint, it can be spotted in binoculars in rural
skies when the Moon is absent from the sky. You will need to be far away
from city lights and you will want to let your eyes adapt to darkness
before trying for the nebula.
The chart at right shows the view looking south around 11:00pm EDT on
October 1st. First of all, find bright Jupiter. It is brighter than any
other star like object in the southern sky. Next look down nearer the
horizon for Formalhaut. It's the brightest star in that region of the sky.
Skat, in Aquarius, forms a roughly equilateral triangle with Jupiter and
Formalhaut.
Putting your binoculars on Skat, locate the fainter stars a, b, c and d
that form the bent diamond shape
extending to the right from Skat. the Helix is to the right of star d. You
will see no color, just a very faint small patch of light. Move your eyes
around the binocular field when you are searching. You may be only able to
see it by using averted vision, that is, looking to the side of it.
Sometimes the first indication that you are close to spotting it is that
there seems to be "something funny" about a certain part of the field of
view. It's definitely a challenge!
When I was making this image I thought about Janus. I sometimes mention Janus
our night programs if we talk about the names
of the months and their origins. He is the Roman god of doorways and beginnings. He's shown
with two faces, one face looking into the past and one face looking into
the future.
The Helix Nebula formed around 10,000 years ago. We are seeing it as it
looked 650 years ago. Most scientists believe that our Sun will meet the same fate a few billion
years from now. We are like Janus. The
Earth, if it survives the Sun's red-giant phase at all, will no longer be
able to sustain life. Hopefully by then we will have found another home.
Sky Events for
October 2021:
The Orionid meteor shower
peaks during the early morning hours on October 21st. The Moon is just
past full and will tend to wash out the view.
Evening Sky:
Saturn, Tethys and Dione, June 11th, 2016. 12.5 inch Newtonian Reflector and
ZWO camera.
Venus
is the brightest star-like object in the western sky after sunset, and
sets about two hours after sunset at the beginning of
the month. It passes by the bright star Antares in Scorpius on the
16th.
Look for
Jupiter
about 25 degrees above the Southeast horizon at dusk at the
beginning of the month. It's in Capricornus this month. Jupiter's dusky belts change from night to night.
Since the planet takes less than ten hours to rotate, you can
watch details move across the disk during an evening. It's always fun to watch the dance of the four Galilean
moons!
Saturn
is upward and to the right of Jupiter in Capricornus.
By the middle of the month it will be due south
around 9:30pm EDT. This is a great opportunity to see Saturn.
Even in good binoculars the tiny oval shape of the planet and
rings can be seen.
If you've never seen Saturn, it's simply spectacular in just about any
size telescope.
In fact, even a good quality 60mm refractor will give a
better view of the ringed planet than Galileo was ever able to see. Saturn
was a puzzle to him. In his low-resolution telescope the planet appeared as three separate
discs - one large disc with a smaller disc on each side of it. A few
years later, he returned to look at the planet when the rings presented
edge-on. His two attendant discs had disappeared! He never solved the
riddle. He would have loved to
see the view available to just about any amateur astronomer today.
Morning Sky:
Mercury
reaches greatest elongation from the Sun on October 25th. This is
a great chance to spot the fleet-footed planet. Watch for it low
in the east in the hour before sunrise.
Constellations:
Able 39, June 6th,
2016, a faint planetary nebula in Hercules. Note the faint
galaxies that can be seen through the nebula!
The views below show the sky looking east at 10:15pm EDT on October
15th. The first view shows the sky with the constellations outlined
and labeled. Star and planet names are in green. Constellation
names are in blue. The second view shows the same scene without
labels. Prominent constellations include
Triangulum, the Triangle,
Aries,
the Ram, and
Cetus,
the Sea Monster.
Auriga, the Charioteer,
with its bright star
Capella,
and
Taurus,
the Bull,
are rising in the northeast. The bright star
Aldebaran,
a red giant representing the eye of the bull, should just be rising.
Above Aldebaran, look for the
Pleiades,
a beautiful open star cluster. Also called the "Seven Sisters," it
has been known since antiquity. In Japan it is known as Subaru, and
the Subaru automobile is named for this cluster. Before the
Gregorian calendar reform in 1582, the Pleiades culminated around midnight
on October 31st, and it has been traditionally associated with Halloween.
Clear moonless fall nights are a great time to hunt down deep sky objects
in Cygnus. The constellation is just about directly overhead and
objects like the Veil Nebula or the Cocoon Nebula are at their best. Don't
expect to see the bright colors that long-exposure CCD images capture.
October 15th, 10:15pm EDT, Looking East
October 15th, 10:15pm EDT, Looking East
On Learning the
Constellations:
We advise learning a few constellations each month, and
then following them through the seasons. Once you associate a particular
constellation coming over the eastern horizon at a certain time of year, you may
start thinking about it like an old friend, looking forward to its arrival each
season. The stars in the evening scene above, for instance, will always be
in the same place relative to the horizon at the same time and date each
October.
Of course, the planets do move slowly through the constellations, but with
practice you will learn to identify them from their appearance. In
particular, learn the brightest stars for they will guide you to the fainter
stars. Once you can locate the more prominent constellations, you can
"branch out" to other constellations around them. It may take you a little
while to get a sense of scale, to translate what you see on the computer screen
or what you see on the page of a book to what you see in the sky. Look for
patterns, like the stars that make up the constellation of Perseus.
The earth's rotation causes the constellations to appear to
move across the sky just as the Sun and the Moon appear to do. If you go
outside earlier than the time shown on the charts, the constellations will be
lower to the eastern horizon. If you observe later, they will have climbed
higher. To observe faint objects, it's always better to wait until they
are high in the sky.
As each season progresses, the earth's motion around the sun
causes the constellations to appear a little farther towards the west each night
for any given time of night. The westward motion of
the constellations is equivalent to two hours per month.
A good book to learn the constellations is
Patterns in the Sky, by Hewitt-White.
For sky watching tips, an inexpensive good guide is
Secrets of Stargazing, by Becky Ramotowski.
A good general reference book on astronomy is the Peterson
Field Guide,
A Field Guide to the Stars and Planets, by Pasachoff. The book retails for around $14.00.
The Virtual
Moon Atlas is a terrific way to learn the
surface features of the Moon. And it's free software. You can
download the Virtual Moon Atlas here.
Apps:
The Sky Safari 6 basic version is free and a great aid for
the beginning stargazer. We really love the
Sky Safari 6 Pro. Both are available for iOS and
Android operating systems. There are three versions. The Pro is
simply the best astronomy app we've ever seen.
The description of the Pro version reads, "includes over 100 million stars, 3 million galaxies
down to 18th magnitude, and 750,000 solar system objects; including every comet
and asteroid ever discovered."
A
nother
great app is the Photographer's
Ephemeris. Great for finding sunrise, moonrise, sunset and
moonset times and the precise place on the horizon that the event will
occur. Invaluable not only for planning photographs, but also nice
to plan an outing to watch the full moon rise. Available for both
androids and iOS operating systems.
Amphibians:
Southern Leopard Frog
When the evening temps begin to drop, listen for
Southern Leopard Frogs calling during their fall breeding period.
Listen also for
Spring Peepers
to call from patches of
woods.
Upland Chorus Frogs sometimes give a very dry, raspy version of their
call in October. Warm-weather species like treefrogs seldom call now, but
you can sometimes find them foraging in trees and shrubs. You can locate many of the frogs and toads that have been calling more
frequently earlier in the year by driving the back roads slowly on rainy nights.
This is a two person job. One person watches the road for amphibians and
one person looks out for other vehicles. Continue to look for salamander
species that breed in the fall, like the Marbled Salamander. Recommended: The Frogs and Toads of North America,
Lang Elliott, Houghton Mifflin Co.
Nature Notes Archives: Nature Notes
was a page we published in 2001 and 2002 containing our observations about
everything from the northern lights display of November 2001 to frog and
salamander egg masses.
Night scenes prepared with The
Sky Professional from Software Bisque
